The objectives are to gain an understanding of the relationship between HCV and depression among drug users, and provide a foundation upon which effective HCV treatment, intervention, and prevention policies may be developed. The specific aim is to identify clusters of drug users with measures of HCV infection and to differentiate these clusters according to depression factors (sociodemographic and/or behavioral risk variables may serve as secondary contributors). Following this population over time, survival analysis and logistic regression techniques will be used to indicate whether drug users with depression factors are more likely to be HCV positive, if depressive symptomatology associated with HCV can be differentiated from that associated with interferon- alpha treatment, and to identify predictor variables for increased depression as a function of increased liver damage. Data will be comprised of an existing data set collected from the Anchorage site of the Cooperative Agreement (CA) for AIDS Community Based Outreach/Intervention Research Program (UO 1), data collected as part of the NIDA-funded (RO 1) Interventions to Reduce HBV, HCV, & HIV in IDUs project (Community Interventions), with Dr. Dennis Fisher. and data collected as part of a project proposed to NIDA on Hepatitis C Virus in U.S. Veterans (HCVV), with Dr. Hugo Rosen. Drug users in Alaska are an ideal sample to use given the high rates of hepatitis infection high rates of depressive symptomatology. access to a minority population of Alaska Natives. and the potential for rapid spread of infectious disease. The comparison with the Oregon project will allow for generalization to other geographical regions. will make a direct comparison of depression factors with other deteriorating liver disease. and will control for drug use.